1. Field of the Invention
The present invention relates to a toner cartridge for use in an electrophotographic image recording apparatus such as printers and copying machines.
2. Description of the Related Art
Toner cartridges can be classified into two types according to their outer shapes: a substantial cylindrical housing and an unconventionally-shaped housing, which is a combination of cylinder and other shapes.
An unconventionally-shaped toner cartridge has a sealing member that closes a toner exit formed in the housing. After the toner cartridge has been installed into the printer, the sealing member is removed so that the toner cascades into the developing unit of the printer.
A conventional cylinder type toner cartridge includes a substantially cylindrical housing and a cylindrical or arcuate shutter rotatably inserted into the cylindrical housing in alignment with a toner exit formed in the cylindrical housing. When the shutter is rotated relative the housing, the shutter rotates between a closing position and an opening position, thereby closing or opening the toner exit. Until the toner cartridge has been installed, the shutter closes the toner exit to hold the toner in the cartridge. After the toner cartridge has been installed, the shutter is rotated to open the toner exit, thereby cascading the toner into the developing unit of the printer.
With the unconventionally-shaped housing, the sealing member that closes the toner exit is removed from the toner exit. Therefore, the toner exit remains open when the empty toner cartridge is taken out of the printer. Thus, the toner may scatter through the toner exit causing soiling of the interior of the printer. Thus, only remnants of the aforementioned unconventionally-shaped housing is difficult to handle when the empty toner cartridge is taken out.
A limitation of the conventional cylindrical housing is that the outer shape of the housing cannot be selected freely. The only way of providing a large-capacity housing is to increase the diameter of the cylindrical housing. Thus, it is difficult for the cylinder type toner cartridge to overcome a problem of limited mounting space in the printer.